Recep Tayyip Erdoğan Üniversitesi Kurumsal Akademik Arşivi
DSpace@RTEÜ, Recep Tayyip Erdoğan Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve yayınların etkisini artırmak için telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Comparative analysis of the impacts of solar, wind, biofuels and hydropower on load capacity factor and sustainable development index
(Elsevier, 2025) Karlılar Pata, Selin; Pata, Uğur Korkut
Achieving carbon neutrality and sustainable development relies on improving the energy sector in any economy. Countries have directed their attention towards sustainable and secure energy sources. At COP28, countries were urged to take action to triple their renewable energy capacity. Investing in renewable energy sources and technologies can indeed promote the decarbonization of the energy system and support sustainable development efforts. To make a strong step, it is of utmost importance to determine which renewable technologies contribute to sustainable development and environmental enhancement. In this context, this study uncovers the influence of disaggregated renewable energy sources (solar, wind, biofuel, and hydropower) on the load capacity factor (LCF) and sustainable development in the United States (US). To this end, the study applies a Fourier approach and uses data from 1990 to 2022. The outcomes show that solar power, wind power, and biofuel are effective contributors to environmental quality and sustainable development. In addition, hydropower has no discernible influence on environmental quality and sustainable development. These results suggest that the US government should support the use of solar energy, wind energy, and biofuels over hydropower for sustainable development and LCF improvement.
A comparative study of helical and spiral flow paths in solar air heaters: Experimental testing and CFD modeling
(Elsevier, 2025) Ben Amara, Walid; Bouabidi, Abdallah; Chrigui, Mouldi; Cüce, Erdem
This study conducted a comparative analysis of Solar Air Heaters (SAHs) with Spiral and Helical flow paths. It evaluates their thermal performance and pressure drop, providing new insights for SAH design and optimization. The prototypes were constructed and tested at the Mechanical Modelling, Energy & Materials (M2EM) Laboratory in Gabes, Tunisia. A numerical model was developed using ANSYS Fluent 2021 R1. The mesh independence was analyzed to ensure accuracy of the numerical results. The results demonstrated excellent agreement between numerical and experimental data, with an average deviation of 4.5 %. The experimental results indicated that the maximum air temperature attained 76.2 °C and 72 °C for the HSAH and the SSAH, respectively at a mass flow rate of 0.01 kg/s. The numerical results showed an increase in air temperature of 62 °C and 59.4 °C for the HSAH and SSAH, respectively, at a mass flow rate of 0.005 kg/s. At higher flow rates, both systems exhibited closer air temperature. Pressure loss analysis showed that the HSAH incurred higher losses (1797.7 Pa) compared to the SSAH (927 Pa) at a mass flow rate of 0.03 kg/s. Consequently, the pumping power was 22 W and 44 W for the SSAH and the HSAH, respectively. In addition, the thermal efficiencies of the two systems became identical at higher flow rates and reached 65 % at a mass flow rate of 0.03 kg/s. Therefore, this study highlights the superiority of the spiral flow path design in terms of thermal efficiency and lower pressure losses compared to the helical configuration.
A new shear deformation theory for composite multilayered shells of revolution with retainment of Koiter's recommendation: Static and free vibration analyses
(Elsevier, 2025) Long, Liji; Yaylacı, Murat; Lezgy-Nazargah M.
Most of the available studies relevant to static and free vibration investigation of composite multilayered shells of revolution are on the basis of single-layer shear deformation theories. Interlaminar continuity conditions of out-of-plane shear stresses are not fulfilled by single-layer shear deformation theories and such models are only suitable for analysis of thin shells of revolution. Following Koiter's recommendation, a refined global-local (RGL) theory with full interlaminar continuity conditions is developed in this study for representing of the displacement fields of the multilayered revolution shell structures. The displacement field of the proposed RGL formulation is not dependent on layers and it has only seven generalized displacement variables. The influence of the initial curvature is incorporated in deriving the proposed RGL shell formulation. The equations of motion of the multilayered shells of revolution are firstly extracted in terms of generalized displacement variables. Then, the obtained governing equations are discretized and solved by means of the standard finite element (FE) method. The accuracy and effectiveness of the proposed RGL shell formulation are confirmed through several numerical examples.
Examining prediction observation explanation method based interactive e-books in terms of high school students' misconceptions, self-regulated learning, cognitive engagement
(Turkish Education Assoc, 2025) Çırakoğlu, Nazmiye; Reisoğlu, İlknur; Toksoy, Seyhan Eryılmaz
This study aims to explain how high school students' misconceptions, cognitive engagement, and self-regulated learning levels change when using interactive e-books based on the prediction, observation, and explanation method for heat and temperature topics. It also aims to examine how the features of interactive e-books support eliminating misconceptions, cognitive engagement, and self-regulated learning. An explanatory mixed method was conducted with 31 high school students in this direction. The misconception detection test, self-regulated learning scale, cognitive engagement scale, and focus group interviews were used as data collection tools. The study found a significant difference between high school students' misconceptions, cognitive engagement, and self-regulated learning levels before and after using interactive e-books based on the prediction, observation, and explanation processes. It was revealed that the interactive e-book is grounded on a specific learning method, covering different multimedia materials, providing critical applications related to the concepts discussed, providing students with a sense of managing their learning process, and allowing observations on examples from everyday life. The study concluded that these characteristics make it easier for the students to understand the differences between different concepts and support cognitive engagement and self-regulated learning.
Microplastics in Lake Sediments in Robert Island, Antarctica
(Central Fisheries Research Institute, 2024) Aytan, Ülgen; Şentürk, Yasemen; Özkan, Korhan; Kandemir, Raif
Microplastic (MP) pollution was investigated in the sediment of lakes on Robert Island in the South Shetland Islands located in the northwest of the Antarctic Peninsula. Sediment samples were taken from a glacial lake (L1) and three coastal lakes (L2, L3 and L4) in March and April 2018 as part of the Turkish Antarctic Science Expedition-II (TAE-II). MPs were counted, and physically (shape, colour, size) and chemically characterized by stereomicroscope and Fourier-transform infrared spectroscopy (FT-IR) respecitvely. Fibers and fragments were found in the coastal lakes, while only fibers were found in the glacial lake sediment. The meanMP concentration was 28.3 mp. L-1±37.9 mp. l-1 sediment in the glacial lake and 49.6 mp. l-1±97.1 mp. l-1 sediment in coastal lakes. A total of six different colours of MPs were found with transparent and blue were dominant. The size of MPs varied between 0.08-2.12 mm (mean 0.96±0.55 mm). FT-IR analysis confirmed that MPs were composed of Ethylene Vinyl Acetate (EVA), Polyethylene terephthalate (PET), Polypropylene (PP), Polymethyl Methacrylate (PMMA), Polyethylene (PE), Polyurethane (PU), and Polyacrylonitrile (PAN). Presence of MPs in the lake’s sediment highlights the vulnerability of Antarctica's environment to this unbounded and unpredictable pervasive pollutant and raises concerns about the potential effects of MPs on its unique ecosystems, which are critical to global climate regulation. More comprehensive research on distribution, characteristics, sources and transport of MPs in this remote region is recommended to fully understand the level of risk that MPs represents to ecosystem health.
